n = int(input())

if n < 2015:
    print(0)
else:
    count = 0
    for y in range(2015, n + 1):
        q = 29
        m = 11
        year = y
        # Zeller's Congruence for Gregorian calendar
        h = (q + (13 * (m + 1) // 5) + (year % 100) + ((year % 100) // 4) + ((year // 100) // 4) + 5 * (year // 100)) % 7
        if h == 0:
            count += 1
    print(count)